Art of purifying petroleum.



No. 649,048. Patented May 8, |900. H. FnAscH.

ART 0F PURIFYING PETROLEUM.

. (Application med nec. 1b, laas.)

(N o M o d el INVENTOR.

WITNESSES4 mi NnRms Prrins co, Pnoroqwo.. wgsumcmm n. a

2 5 volve the distillation of the oil.

NiTED STATES PATENT @Erica HERMAN ERAsci-i, oE cLEvELAND, oI-no, AssIcNoR fro THE soLAE REEINING COMPANY, or onio.

RT OF PURIFYING PETROLEUM.

srEcI'EI'cA'rIcN forming part of Letters Patent No. 649,048, dated May s, 1900.

Application tiled December 10, 1888.

io of petroleum,undistilled and distillate,of that class of petroleum distinguished by the presence of a large proportion of sulfur compounds which resist the ordinary treatment for the removal of sulfur and which render the oil unfit for general use on account of their Very disgusting odor. This oil usually contains more than one-half of one per cent. of sulfur, and being found chiefly in Canada and at Lima, in the State of Ohio, is generally zo known as Canadian oil or Lima oil. Ina

prior patent, No. 378,246, dated February 21, 1888, and in prior applications for patents I have described and claimed processes of deodorizing and purifying such oil, which in- The present invention relates to a process of purification which is independent of distillation.

In an application for patent iiled November l, 1888, Serial No. 289,747, I have described 3o and claimed a process in which the purification of the products sought thereby is'not dependent upon their distillation; but said application is, except as to one improvement, limited to the treatment of undistilled pe- 3 5 troleum, which term includes both there and inthe present specification reduced oil, crude oil, residuums of distillation, and the like. The present invention is not so limited, but extends to the treatment of oils generally 4o and covers the treatment of distillates as well rying this latter into effect-namely, the operation of superheating the liquid oil, as hereinafter explained.

Before the date of mysaid several inventions it was the custom in Canadian refineries and 5o in some reiineries in the United States to take the burning-oil distillates or kerosene which serial No. zeai. (No specimens.)

tillate obtained therefrom has the malodor of the original skunk. My opinion is that the deodorization is due to the formation of an in odorous ox'idated form ofthe skunk, in which the oxygen is so loosely bound that on distillation it is liberated and the skunk reduced to its original malodorous form. This opinion is in harmony with the further fact that by the aid'of agents whose position as oxidants has been generally recognized I have produced a deodorized oil which yields on distillation an oil having the malodor of the original skunk. The malodorous distillate, moreover, from the inodorous oil, whether this has been deodorized with the plumbate-of-sodium solution or with one or other of the common oxidating agents, gives, with a clear solution of plumbate of sodium, the reaction which has come to be regarded among workers in this class of oil as characteristic of the skunk thereof-that is to say, the said malodorous distillate if clear and free from hydrogen sulfid turns to a canary-yellow color on addition thereto of a clear plumbate-of-sodium solution. It' the oil contains hydrogen sulid, this substance yields a black precipitate with the solution ot' the plumbate of sodium, which tends to conceal the canary-yellow. Asexamples of the substances whose positions as oxidants have been generallyrecognized and by the aid-of whi'ch'the aforesaid deodorized oil can be produced may be mentioned the solutions of chromic, stannic',"a1senic, and nitric acids, gaseous nitrous aci 1e hypochlorites of calcium, sodium, and potassium, the manganates and permanganates of potassium, sodium, and other metals, the peroxid of barium, mercuric nitrate, and the ferrate salts. Binoxid of manganese may also IDU be mentioned. The metallic oxids which are soluble in skunk-bearing oil-such as the oitids of lead, copper, cadmium, silver, mercury, and other metalieeiptable from their acid solutions with hydrogen sulfidand also suitable compounds of such oxids are likewise capable (as I have found) of acting as oxidating agents toward `the skunk, and thus deodorizing skunk-bearing oil, in such manner that the distillation of the sodeodorized oil, from which the metal has been precipitated as suliid by powdered sulfur, yields a malodorous distillate showing the before-mentioned yellow discoloration on addition thereto of plumbate0f-sodium solution.

My present invention is based upon the addition al discoveries which I have madeii rst, that the inodorous compound of oxygen and skunk, (or whatever the product of the treatment may be,) although so unstable as to suffer decomposition by distillation of the oil containing it, is nevertheless capable of sus taining temperatures above the distillingpoint of said oil, provided it is during such superheatin g subjected to a su peratrnospheric pressure sufficient to prevent the distillation of the oil; second, that the said unstable compound is produced by su perheatingthe liquid oil under the above conditions more readily and rapidly than it will be formed in the cold or than at the temperature of distillation, and, third, that such rapid deodorizatiomwith the aid of superheating, can be effected without at the same time inducing objectionable decompositions in the oil. In accordance with the present invention, therefore, the skunk-bearing oil (distillate or undistilled) is'subjected to the action of an oxidating agent or agents at a temperature above the temperature of distillation of said oil, vaporation thereof being prevented by an accumulation of superatmospheric pressure in the vessel wherein the treatment is performed. Chile the treatment may be carried out with substances generally which act as oxidants toward the skunk, there are advantages in using the oxidating agent or agents in a solid subdivided condition rather than in aqueous solution as being less apt to emulsify the oil and as being more readily separable therefrom. It is also considered most advantageous in many, if not in most cases, to employ as the oxidatin g agent or agents one or more of the metallic oxids soluble in skunk-bearing oil or one or more of the compounds of such oxids suitable for the purpose. As examples of suitable compounds maybe mentioned the carbonates and the fatty or resinous salts of the metals which yield oxids soluble in skunlcbearing oil. The chromatc, manganate, and borate of lead and the boratc of copper may be mentioned as further examples. lVhen metal, as well as oxygen, unites with the skunk in solution in the oil, said metal may be removed-as, for example, by precipitation with sulfur in powder-or it may be allowed to remain if its presence is not disadvantageous to the use to which the oil is to be put. Other reduced residues (as well as any excess of the oxidating agents) may be removed in any suitable way, or, where not injurious to the oil for the purpose for which it is designated, they may be left in the oil. The oil, with the oxidating agent or agents, is superheated in a close vessel to prevent volatilization of the oil and in the case of the heavier products also to prevent the formation of tarry bodies, and agitation is employed in conjunction with the superheating under pressure to bring about a thorough admiiture and suspension of the oXidatin g agent or agents in the oil. Preferably the said agent or agents are employed in large excess of the quantity theoretically necessary to combine with the sulfur compounds, so as to insure a more thorough and rapid deodorization of the oil. The excess which settles to the bottom when the treatment is ended can be used on a fresh batch of oil. The completion of the deodorizing operation can be determined by withdrawing a sample and ascertaining if it is free from the malodor of skunk, or if, being clear, it does not change color on addition to the sample of plumbateof-sodium solution.

The new process may bc applied to oil which has been subjected to a prior treatment with sulfuric acid or to oil which has not been so treated. i

To one hundred barrels of the skunk-bearing oil to be treated it will generally suffice to use two hundred pounds of finely-divided dry lead oXid (litharge) or a chemicalequivalent of any other of the metallic oxids soluble in skunk-bearingoil. Vith other oxidants corresponding proportions may be employed. The oil andthe oxidating agent or agents are agitated together at a temperatn re above the distilling-point of the oil under treatment in a close vessel at a superatmospheric temperatu re sufficient to prevent vaporization of said oil. l/Vhen using litharge or other metallic oXid soluble in skunky oil as the oxidant, it is well to use in conjunction therewith a fatty or resinous acid to aid in effecting the solution. For example, about tive hundred pounds of powdered colophonic acid, or, in other Words, of common rosin, may be used with the tWo hundred pounds of litharge mentioned above. With litharge and rosin the deodorization should be complete in eight or ten hours or less. If no rosin is used, a longer time may be required. Vhen the deodorization is complete,the deodorized oil may be drawn olf from the undissolved matter, which settles to the bottom on the cessation of the agitation.

For heavy oil, whether distillate or reduced oil or resid u um of a distilling-point below 400 Fahrenheit, the treatment may be carried on at about 400 Fahrenheit, and in case of heavy oil Whose distilling-point is as much as 400 Fahrenheit the temperature of the treatment should of course be increased.

With kerosene or hurning-oil the temperan IIO ture of treatment may be below 3000 Fahrenheit and with naphtha it may be below the boiling-point of Water; but it is always to be above the distilling-point of the particular. oil under treatment.

I claim as my invention or discoveryl. The process of deodorizing oil of the Canadian or Lima class, by the prolonged subjection of the skunk-bearing oil to the action of an oxidating agent or agents in a closed vessel at a temperature above the distilling-point of the said oil under atmospheric pressure and under a pressure of vapor in said vessel above the vapor tension of the oil at said ternperature, so that the oil is retained in the liquid state during such subjection,vaporization thereof being prevented by the excess of said pressure over the vapor tension of the said liquid oil, substantially as described.

2. The process of deodorizing oil of the Canadian or Lima class, by the prolonged subj ection of the skunk-bearing oil to the action of a solid subdivided oxidating agent or agents in a closed vessel at a temperature above the distilling-point of the said oil under atmospheric pressure and under a pressure of vapor in said vessel above the vapor tension of the oil at said temperature, so that the oil is retained in the liquid state during such subjection, vaporization thereof being prevented by the excess of said pressure over the vapor tension of the said liquoil, substantially as described. J/ y 3. The process of deodorizing oil of the Canadian or Lima class, bythe prolonged subjection of the skunk-bearing oil to the action of one or lnore metallic oxids soluble in skunkbearing oil in a closed vessel at a temperature above the distilling-point of the said oil under atmospheric pressure and under a pressure of vapor in said vessel above the vapor tension of the oil at said temperature, so that the oil is retained in the liquid state during such subjection, vaporization thereof being prevented by the excess of said pressure over the vapor tension of the said liquid oil, substantially as described.

In testimony whereof I have signed this speciication in the presence of two witnesses.

HERMAN FRASCH.

Vitnesses:

F. W. LOTHMAN, WM. V. KEEGAN. 

